The nuts should be accessible from inside the coach, by opening the AC's panel on the ceiling, Don. I'm not familiar with exactly what unit is on your model coach, but I don't think you need to get on the roof to do this; others here with direct knowledge of the Duo-Therm or Coleman, whichever, on an '02 Contessa should chime in.
Just a few turns with a wrench while standing on the floor may be all it takes to stop the leaking until a tech can check things. If needed, perhaps someone else can get a crescent wrench up there and do it for you. On ours, you just slip your fingers between the wood frame and the ceiling along the front edge and tug down to open the panel, which is hinged at the back, and catch the foam filter that's held up by the panel. If you've never had it open before, now may be a good time to clean the filter if it's very dirty - gently wash and air dry it, or vacuum it, or buy a replacement.
On ours, they've used long bolts through threaded brackets rather than nuts. So a nut driver or small socket on the bolt heads is an easy adjustment. Note in the photo the bolt head locations, one through the bracket just to the left of the orange wire, and the other slightly hidden between the two yellow wires on the right. If you tackle this, just don't crank the bolts down hard or you risk warping the gasket up top and making a bad thing worse. Just make sure the bolts aren't loose.
Clicking on the photo may provide a larger image.
Joel
